Effect of aging of true radiocolloids on their sorption

The model for microcomponent sorption on an ion exchanger in the H form und er conditions of formation of trace hydroxide colloid of the amphoteric nat ure predicts the appearance of a plateau or two sharp maxima, separated by a horizontal section, in the sorption isotherm log<(epsilon)over bar>-pH. T he occurrence of a plateau is attributed to a phase transition (ion-molecul ar species reversible arrow trace colloid) in the system. The maxima in the isotherm are due to aging of the trace colloid formed at low pH and also t o its dissolution in the region where anionic complexes of the microcompone nt prevail. Ht is demonstrated with attraction of the published data on sor ption of trace Fe(III) that heteronucleation of iron hydroxide on the surfa ce of colloid impurities can be a reason for a trace colloid to behave simu ltaneously as a true and an adsorbed colloid.